Multi-column addressing mode memory system including an integrated circuit memory device

ABSTRACT

A memory system includes a master device, such as a graphics controller or processor, and an integrated circuit memory device operable in a dual column addressing mode. The integrated circuit memory device includes an interface and column decoder to access a row of storage cells or a page in a memory bank. During a first mode of operation, a first row of storage cells in a first memory bank is accessible in response to a first column address. During a second mode of operation, a first plurality of storage cells in the first row of storage cells is accessible in response to a second column address during a column cycle time interval. A second plurality of storage cells in the first row of storage cells is accessible in response to a third column address during the column cycle time interval. During a third mode of operation, a first plurality of storage cells in a first row of storage cells in a first memory bank is accessible in response to a first column address. A second plurality of storage cells in a second row of storage cells in a second bank is accessible in response to a second column address. A third plurality of storage cells in the first row of storage cells is accessible in response to a third column address and a fourth plurality of storage cells in the second row of storage cells is accessible in response to a fourth column address. The first and second column addresses are in a first request packet and the third and fourth column addresses are in a second request packet provided by the master device.

FIELD OF THE INVENTION

The present invention relates to high speed signaling.

BACKGROUND

A memory system typically includes a master device, such as a memorycontroller or graphics controller, and a plurality of integrated circuitmemory devices for storing data. An integrated circuit memory devicetypically includes a plurality of storage cells for storing data, suchas pixel information. The plurality of storage cells may be arranged inan array or memory bank. The integrated circuit memory device mayinclude a plurality of memory banks.

Data is written to and read from the integrated circuit memory device inresponse to one or more commands included in read and/or writetransactions between the integrated circuit memory device and the masterdevice. For example, data is generally transferred from memory banks tosense amplifiers in response to an ACTIVATION (ACT) command on a controlinterconnect. The data may then be transferred from the sense amplifiersthrough an integrated circuit memory device interface and onto a datainterconnect in response to a READ (RD) command on the controlinterconnect.

Data stored in the plurality of storage cells is typically transferredto the sense amplifiers one row of storage cells at a time. A row ofstorage cells is typically referred to as “a page”. A column address isoften provided to an integrated circuit memory device by the masterdevice to access data within a selected page. A column address may beincluded in a request packet or with a command provided by the masterdevice to the integrated circuit memory device.

Memory systems are utilized in different manners depending upon whetherthe memory system is used for a computational application, such as ageneral-purpose computer, or graphics application, such as a gameconsole. For example in a graphics application, a large portion ofmemory requests by a graphics controller, have small transfer sizes of16 to 32 bytes and little spatial or temporal locality. This is becauseeven though the image itself is large, the polygon fragments that makeup the image are small, getting smaller over time, and are stored withlittle relation to each other. Only a small portion of a page may needto be accessed in rendering a current image in a graphics application.In contrast, computational applications may have 256 byte cache lineblock transactions. In a computational application, a controlinterconnect or bus is often shared across multiple integrated circuitmemory devices; where a control bus is often dedicated to eachintegrated circuit memory device in a graphics application. Incomputational applications, address mapping is typically random acrossmultiple memory banks; while address mapping is generally limited topages of an integrated circuit memory device in graphics applications.Transaction queues in the master device are reordered to minimize memorybank conflicts in both computational applications and graphicsapplications, but also reordered to maximize memory bank hits in agraphics application. In a computational application, there aregenerally a limited number of outstanding read transactions in thetransaction queue, for example 10; while there may be hundreds oftransactions in a graphics application.

Memory systems in a graphics application have accommodated the need forsmall transfer granularity by having more transfers (reducing a columncycle time interval t_(CC).) However, this will cause the cost of theintegrated memory circuit device to increase, since the performance ofthe memory core that contains the interface to the sense amplifiers willlikely have to increase as well. In any case, this is an inefficientsolution because the size of each transfer remains the same; the unusedportion of the data fetched remains the same.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of a memory system including anintegrated circuit memory device and master device.

FIG. 2 illustrates pixel mapping of an integrated circuit memory deviceshown in FIG. 1.

FIG. 3 is a timing diagram illustrating a first and second mode ofoperation using a single and dual column addressing mode, respectively,of the integrated circuit memory device shown in FIG. 1.

FIG. 4 is a request packet format having two column addresses for a rowof storage cells (or page) of the integrated circuit memory device shownin FIG. 1.

FIG. 5 illustrates a first time mapping from a page of the integratedcircuit memory device to an external interconnect of the memory systemshown in FIG. 1 using two column addresses.

FIG. 6 illustrates a second time mapping from a page of the integratedcircuit memory device to an external interconnect of the memory systemshown in FIG. 1 using two column addresses.

FIG. 7 is a timing diagram illustrating a third mode of operation usingtwo dual column addresses or a quad column addressing mode of theintegrated circuit memory device shown in FIG. 1.

FIG. 8 illustrates request packet formats having four column addressesfor quad column addressing mode of the integrated circuit memory deviceshown in FIG. 1.

FIG. 9 is a simplified block diagram of the integrated circuit memorydevice that receives four column addresses for four independent columnaccesses of a page.

FIG. 10 is a timing diagram and memory bank content mapping illustratinga first mode of operation using dual column mode addressing of theintegrated circuit memory device shown in FIG. 9.

FIG. 11 is timing diagram and memory bank content mapping illustrating asecond mode of operation using quad column addressing mode of theintegrated circuit memory device shown in FIG. 9.

DETAILED DESCRIPTION

A memory system includes a master device, such as a graphics controlleror memory controller, and at least one integrated circuit memory deviceoperable in a dual or multi-column addressing mode. The integratedcircuit memory device includes, among other circuit components, aninterface and column decoder to access a row of storage cells or a pagein a memory bank. During a first mode of operation, a first row ofstorage cells in a first memory bank is accessible in response to afirst column address. During a second mode of operation, a firstplurality of storage cells in the first row of storage cells isaccessible in response to a first column address during a column cycletime interval. A second plurality of storage cells in the first row ofstorage cells is accessible in response to a second column addressduring the column cycle time interval. During a third mode of operation,a first plurality of storage cells in a first row of storage cells in afirst memory bank is accessible in response to a first column address. Asecond plurality of storage cells in a second row of storage cells in asecond bank is accessible in response to a second column address. Athird plurality of storage cells in the first row of storage cells isaccessible in response to a third column address and a fourth pluralityof storage cells in the second row of storage cells is accessible inresponse to a fourth column address. The first and second columnaddresses are in a first request packet and the third and fourth columnaddresses are in a second request packet provided by the master device.

FIG. 1 illustrates a memory system 140 including an integrated circuitmemory device 100 coupled to master device 130 by interconnects RQ andDQ. Integrated circuit memory device 100 includes N memory banks 101, ina memory core 100 a, and an interface 100 b.

Memory banks 101 include individual memory banks having a twodimensional array of storage cells. In an embodiment, memory banks 101include 16 memory banks. In an embodiment, a memory bank includes 2048rows of storage cells or pages. Each row includes 64 addressable columnsthat each store 16 bytes of information (or 1024 bytes per page). Inembodiments, storage cells of memory banks 101 may be dynamic randomaccess memory (DRAM) cells, static random access memory (SRAM) cells,read-only memory (ROM) cells, or other equivalent types of memorystorage cells. In an embodiment, integrated circuit memory device 100 isan XDR™ DRAM integrated circuit memory device provided by Rambus Inc. ofLos Altos, Calif., USA.

Reading and writing to memory banks 101 are initiated by row decoder 122and dual column decoder 123 in response to row and column addresses,respectively. A plurality of storage cells or referred to as row 112(also referred to as a page) outputs a plurality of data (or set ofdata) to sense amplifiers 121 in response to a row address provided torow decoder 122 followed by a column address or column addressesprovided to dual column decoder 123 on internal interconnect A. Memorydevice 100 includes an internal interconnect A for providing control andaddress signals for addressing a storage location in memory banks 101.Interconnect A is coupled to circuitry 105 for coupling interface 100 bto core 100 a. Pipeline register 102 is coupled to circuitry 105 andreceiver 108. External interconnect RQ is coupled to receiver 108 andcarries external control and address signals between interface 100 b andmaster device 130. In an embodiment, interconnect RQ is a twelve signalline unidirectional control/address bus. Internal interconnect S, in anembodiment, is an internal bidirectional bus for providing read/writedata signals between sense amplifiers 121 memory banks 101. InterconnectS is coupled to circuitry 106 and 107 for coupling interface 100 b tocore 100 a. Pipeline registers 103 and 104 are coupled to circuitry 106and 107, respectively. Transmitter 109 and receiver 110 are coupled topipeline registers 103 and 104, respectively. An external interconnectDQ transfers external bidirectional read/write data signals and iscoupled to transmitter 109 and receiver 110 as well as master device130. In an embodiment, interconnect DQ is a sixteen signal linebidirectional data bus.

Dual column decoder 123 allows independent access to one or moreaddressable columns in a selected row 112 during a column cycle timeinterval t_(CC) in response to one or more column addresses provided oninternal interconnect A. In an embodiment, dual column decoder 123 isinitialized to a single, dual, quad or multiple columns addressing modedecoder in response to a mode control signal 125. In an embodiment, modecontrol signal 125 is provided from an initialization register at memorysystem 140 initialization or power-up. In an alternate embodiment, modecontrol signal 125 is provided by master device 130 by way ofinterconnect RQ and internal interconnect A at initialization or duringtypical operation.

The pipeline registers 102, 103, and 104 are used for synchronization ofthe information between the internal and external interconnects.Registers 102-104 may also be used for generating delay, as would berequired if the internal and external interconnects used a differentnumber of signals. Although memory device 100 shows a single level(clock cycle) of pipeline registers, two or more levels (clock cycles)of delay are used in alternative embodiments.

In an embodiment, differential signals are transferred between memorydevice 100 and master device 130 on interconnect RQ, interconnect DQ anda CLOCK (CLK) line.

A CLK line provides a clock signal Clk to registers 102-104 forsynchronizing integrated circuit memory device 100 transactions. In anembodiment, a clock signal Clk is provided to integrated circuit memorydevice 100 by master device 130. In alternate embodiments, a clocksignal Clk is provided by another source, such as a clock generator. Inother embodiments, a clock signal Clk serves as a reference for a clockrecovery circuit component, which generates the actual clocking signalused with integrated circuit memory device 100.

In an embodiment, interface 100 b includes a plurality of conductingcontacts, such as pins and/or balls, for coupling to interconnect RQ,interconnect DQ and one or more CLK lines. In an embodiment, interface100 b includes twelve pins for coupling to interconnect RQ and sixteenpins for coupling to interconnect DQ. As one of ordinary skill in theart would appreciate, more or less contacts may be provided in alternateembodiments.

In embodiments, interconnects described herein include a plurality ofconducting elements or conducting paths such as a plurality of wiresand/or metal traces/signal lines. In an embodiment, a single conductingpath illustrated in the Figures may be replaced by multiple conductingpaths and multiple signal paths illustrated in the Figures may bereplaced by a single conducting path. In embodiments, an interconnectmay include a bus and/or point-to-point connection. In an embodiment,interconnects include control and data signal lines. In an alternateembodiment, interconnects include only data lines or only control lines.In still other embodiments, interconnects are unidirectional (signalsthat travel in one direction) or bidirectional (signals that travel intwo directions).

In embodiments, master device 130 is a general-purpose processor, memorycontroller, network controller or graphics processor.

In an embodiment, integrated circuit memory device 100 is positioned ona substrate in a memory module having multiple integrated circuit memorydevices. In an alternate embodiment, master device 130, memory device100 and associated interconnects are in an integrated monolithiccircuit.

As one of ordinary skill in the art would appreciate, other embodimentsof an integrated circuit memory device 100 and master device 130, singlyor in combination are available.

FIG. 2 illustrates pixel-mapping 200 of an integrated circuit memorydevice 100 shown in FIG. 1. Pixel information or data stored in multiplememory banks are mapped to tiles of an image. In particular, a tile 201or portion of an image, such as triangle 202, is stored in memory bank10 at page or row 112 of storage cells. Pixel information and/or datafor an image are stored in multiple banks and rows that are accessed torender an image on a display at a particular time. Column addresses 203identify stored pixel information for rendering tile 201 and inparticular an image of a triangle 202. As illustrated, if triangle 202is rendered at a particular time, only portions or pixel information ata few particular column addresses of row 112 need to be accessed. Mostof row 112 does not contain pixel information regarding triangle 202.

To reconstruct the image of triangle 202, multiple column addresses areprovided to an integrated circuit memory device 100 for independentlyaccessing portions of a row or page of storage cells during a columncycle time interval t_(CC). Since each portion of the triangle that isto be retrieved is relatively small, it is desirable that small transfergranularities, or small transfer sizes per column address, be used forthese types of graphics applications for the extensive rendering ofimages comprising small triangles. In particular memory device 100includes a dual or generally multi-column decoder 123 that decodes oneor more column addresses for accessing a plurality of storage cells in arow of a memory bank or page.

FIG. 3 is a timing diagram 300 illustrating a first mode of operationand a second mode of operation using dual column mode addressing of anintegrated circuit memory device 100. Timing diagram 300, as well asother timing diagrams illustrated herein, provides various methodembodiments of operating memory system 140, in particular integratedcircuit memory device 100. One of ordinary skill in the art wouldappreciate that timing diagrams described herein may include other orless memory transactions in alternate embodiments. In an embodiment, amemory transaction between integrated circuit memory device 100 andmaster device 130 is a collection of request packets used to completeaccess to one or more memory banks. A request packet represents one ormore signals asserted at particular bit windows on particular signallines on interconnect RQ in an embodiment. Format embodiments of requestpackets are shown in FIG. 4 and described below.

While certain timing constraints are illustrated in FIG. 3, as one ofordinary skill in the art would appreciate, other timing constraints arepossible in other embodiments. In an embodiment, a cycle time intervalt_(cycle) between clock edges of a clock signal is approximately 1.25ns. A column cycle time interval t_(CC) is defined as two cycle timeintervals t_(cycle) in an embodiment. A row cycle time interval t_(RC)is an amount of time or time interval between successive ACT commands tothe same memory bank of integrated circuit memory device 100. A timeinterval t_(RR) is an amount of time to open a selected row/pageconsecutively from different memory banks of the integrated circuitmemory device 100 or an amount of time or time interval betweensuccessive ACT commands to different memory banks. A column cycle timet_(CC) is an amount of time or time interval between successive RDcommands or between successive WRITE (WR) commands to the same memorybank or to different memory banks. There are two column cycle timeintervals t_(CC) for every time interval t_(RR) in an embodiment.

In a first or a computational mode of operation (accessing a page usinga single column address), one ACT command, one RD command and aPRECHARGE (PRE) command are asserted on interconnect RQ by master device130 to integrated circuit memory device 100. Dual column decoderaccesses a single column in row 112 responsive to a single columnaddress. In this mode of operation, a mode control signal 125 has beenasserted to dual column decoder 123 so that dual column decoder 123,operating as a single column decoder, decodes a single column addressper each column cycle time interval t_(CC). A single column address isincluded in a COL or COLM request packet that also include a RD or WRcommand and is transferred from master device 130 to integrated circuitmemory device 100 in an embodiment. In an embodiment, a COLM request isa masked operation that is used with a WR command and not a RD command.In an alternate embodiment, either a COL or COLM request may be usedwith a RD command.

In a second or a graphics mode of operation (accessing a page using twocolumn addresses), one ACT command, one RD command and a PRE command arealso asserted on interconnect RQ by master device 130 to integratedcircuit memory device 100. In an alternate embodiment, two RD commandsare provided. Dual column decoder accesses a first and second column inrow 112 responsive to two respective column addresses. In this mode ofoperation, a mode control signal 125 has been asserted to dual columndecoder 123 so that dual column decoder 123 decodes two column addressesper each column cycle time interval t_(CC). Two column addresses may beincluded in either a COL or COLM request packet, illustrated in FIG. 4that also includes a RD or WR command and is transferred from masterdevice 130 to integrated circuit memory device 100 in an embodiment. Inan embodiment, additional bank bits may be included in a request packetto identify a particular memory bank or multiple memory banks (forexample dual memory banks) that are accessed by respective dual columndecoders. Thus, dual or multi-column addressing enables smaller datagranularity since the data transfer size between integrated circuitmemory device 100 and master device 130 remains the same but a firsthalf of the data transferred is obtained at a first column address and asecond half of the data transferred is obtained from a second columnaddress.

In response to a request packet that includes two independent columnaddresses, in particular, column address values in fields CP[8:4] (firstcolumn address) and C[8:4] (second column address) in either COL requestpacket 401 and COLM request packet 402, 256 bits or 32 bytes are readonto interconnect DQ (or on sixteen signal lines of interconnect DQ) percolumn cycle time interval t_(CC). In other words, 512 bits or 64 bytesare read onto interconnect DQ per time interval t_(RR).

FIGS. 5 and 6 illustrate a first time mapping 500 and second timemapping 600, respectively, from a page of the integrated circuit memorydevice 100 to an external interconnect DQ. FIG. 5 illustrates how page502 of memory bank 501 can have a first half (or odd half of open page502 a) accessed responsive to a first column address value in a firstcolumn field CP[8:4] in a COL request packet 401 and a second half (oreven half of open page 502 b) accessed in response to a second addressin a second column field C[8:4] in the same COL request packet 401 shownin FIG. 4. A COLM request packet 402 may likewise be used in anembodiment.

FIG. 5 illustrates how an interleaved 32 bytes per column cycle timet_(CC) are output onto an interconnect DQ having 16 signal lines. Afirst 16 bits by 8 bits is obtained from an odd half of open page 502 aand output on interconnect DQ and then a second 16 bits by 8 bits areobtained from an even half of open page 502 b and output on interconnectDQ. In the embodiment illustrated by FIG. 5, a plurality of data isoutput from integrated circuit memory device 100 on interconnect DQ frominterleaved odd and even halves of a page 502. Column granularity percolumn cycle time interval t_(CC) is 128 bits or 16 bytes. Columngranularity per time interval t_(RR) is 512 bits or 64 bytes.

FIG. 6 illustrates how 32 bytes per column cycle time t_(CC) from bothhalves of page 602 are simultaneously output on an interconnect DQhaving 16 signal lines. A first 8 bits by 16 bits from an odd half ofopen page 602 a and a second 8 bits by 16 bits from an even half of anopen page 602 b of open page 602 in memory bank 601 is outputsimultaneously on interconnect DQ in an alternate embodiment. Columngranularity per column address remains the same at 128 bits or 16 bytes.Column granularity per column cycle time interval t_(CC) is also 256bits or 32 bytes in the embodiment illustrated by FIG. 6.

FIG. 4 illustrates formats of request packets 400-404, in particularrequest packets having two or more column addresses for accessing a pageof an integrated circuit memory device 100. A request packet representscontrol and address signals, such as commands and column addresses,asserted by master device 130 on interconnect RQ to integrated circuitmemory device 100 in an embodiment. Request packets consist of 24 bitsor logical values that may be represented by voltage values provided oninterconnect RQ (RQ0-RQ11 data signal lines) and sampled at interface100 b on two successive clock signal edges (indicated as “Even” and“Odd” in FIG. 4) in an embodiment. As one of ordinary skill in the artwould appreciate, other request packets having different formats and/orsizes may be used in alternate embodiments.

Request packet formats 400-404 are distinguished by an opcode field(OP[X]), which specifies the opcode of a desired command. Reservedfields are identified by “rsrv”.

ROWA request packet 400 has opcode fields OP[3:2] for an ACT command. Amemory bank address field BA[3:0] and a row address field R[10:0] arealso included for providing a bank address and a row address.

COL request packet 401 has opcode field OP[3:0] for a RD command and WRcommands. A memory bank address field BC[3:0], a first column addressfield C[8:4] (for example, for accessing data in a column address of apage selected by the row address values in R[10:0]), a second columnaddress field CP[8:4] (for example, for accessing data in a secondcolumn address of the page selected by the same row address values inR[10:0]) and a sub-opcode field (WRX) are specified for the RD and WRcommands. In an embodiment, more than two column addresses may beincluded in a request packet for accessing more than two columns in apage during a column cycle time interval t_(CC).

COLM request packet 402 has opcode field OP3 for a MASKED WRITE (WRM)command. A memory bank address field BC[3:0], a first column addressfield C[8:4], a second column address field CP[8:4], similar to COLrequest packet 401, and mask fields M[7:0].

ROWP request packet 403 has opcode fields OP[3:0] for PRE and REFRESH(REF) commands. A memory bank address field BP[3:0] and sub-opcode fieldPOP[2:0] are specified for the PRE command. Sub-opcode fields ROP[2:0]are specified for a REF command.

COLX request packet 404 includes other opcode fields OP[3:0] andsub-opcode fields XOP[3:0].

FIG. 7 illustrates a third time mapping 700 from a page of theintegrated circuit memory device to an external interconnect DQ of thememory system shown in FIG. 1. FIG. 7 illustrates a time mapping similarto FIG. 3 except that four independent column accesses (quad), ascompared to two (or dual) column accesses, are performed in each timeinterval t_(CC) using four column addresses in two request packets.Please note for the embodiment illustrated in FIG. 7, a column cycletime interval t_(CC) is twice the column cycle time interval t_(CC) usedin an embodiment illustrated by FIG. 3. Four column addresses areobtained by using a column field CP[8:4], a column field C[8:4] and aselect field SEL or SEL value in either COL request packet 801 or COLMrequest packet 802, respectively, described in detail below andillustrated in FIG. 8. A select or logic value of 1 or 0 identifieswhich group of memory banks, as shown in FIG. 9, the column addressvalues in column address fields C[8:4] and CP[8:4] is directed toward. Aselect field SEL that has a “0” value indicates that the column addressvalues are directed toward memory banks 901 and 902; while a selectfield SEL that has a “1” value indicates that the column address valuesare directed toward memory banks 903 and 904 of integrated circuitmemory device 900. In an alternate embodiment, memory banks arestaggered or memory banks 901 and 904 are grouped and memory banks 902and 903 are grouped in order to save on peak current.

In alternate embodiments, three memory bank address bits or two memorybank address bits may be used for a column address with the use of a SELbit.

In the embodiment illustrated by FIG. 7, 128 bits or 16 bytes are outputfrom integrated circuit memory device 100 on interconnect DQ per columncycle time interval t_(CC) per each of the four column addresses; while512 bits or 64 bytes are output per time interval t_(RR).

FIG. 8 illustrates formats of request packet 400, 801, 802, 403 and 404,in particular request packets having four column addresses forindependently accessing a page of an integrated circuit memory device100 during a column cycle time interval t_(CC). FIG. 8 illustratessimilar request packets shown and described in regard to FIG. 4.However, each request packet 801 and 802 provides a potential for fourcolumn addresses to a page per column cycle time interval t_(CC) (2explicit addresses with varying the SEL bit) instead of a maximum of twocolumn addresses per column cycle time interval t_(CC) in each requestpackets 401 and 402. In particular, a SEL field is used to identifywhich group of memory banks the two column address values in respectivecolumn address fields C[8:4] and CP[8:4] are directed toward. Addressbit value CP[8] is now positioned, as compared to FIG. 4, at the clocksignal odd edge of RQ11 and a SEL bit value is provided at the clocksignal odd edge of RQ10 in COL and COLM request packets 801 and 802.

FIG. 9 is a simplified block diagram of the integrated circuit memorydevice 900 that receives four column addresses for independentlyaccessing four columns in a page during a column cycle time intervalt_(CC). In an embodiment, integrated circuit memory device 900 is usedinstead of integrated circuit memory device 100 in memory system 140described above. In particular, FIG. 9 illustrates integrated circuitmemory device 900 having a plurality of memory banks 901, 902, 903 and904. In an embodiment, each of the memory banks 901, 902, 903 and 904includes four memory banks. In an embodiment, memory banks 901 (evenmemory banks B0, B2, B4, B6) and 902 (odd memory banks B1, B3, B5, B7)are grouped and memory banks 903 (odd memory banks B1, B3, B5, B7) and904 (even memory banks B0, B2, B4, B6) are grouped. In an embodiment, apage in like referenced banks may be simultaneously accessed. Forexample, a page may be accessed from even memory bank B0 of memory bank901 and even memory bank B0 of memory bank 904. In effect, two separatememory banks operate as one memory bank in accessing a page.

Memory transactions, in particular memory commands, are input to controllogic 905 from interconnect RQ. Control logic 905 includes receiver 108,pipeline register 102 and circuitry 105 as seen in FIG. 1 in anembodiment. Control logic 905 then provides memory control signals,including column and row addresses, to row/col decoders 910, 911, 912and 913. In an embodiment, each row/col decoder 910, 911, 912 and 913operates similarly to interconnect A, row decoder 122 and dual columndecoder 123 shown in FIG. 1. Likewise, read pipes 906 and 908 coupled tomemory banks 901/903 and 902/904 operate similar to sense amplifiers121, circuitry 106, pipeline register 103 and transmitter 109 shown inFIG. 1. Also, write pipes 907 and 909 coupled to memory banks 901/903and 902/904 operate similar to sense amplifiers 121, pipeline register104, circuitry 107 and receiver 110.

Memory banks 901 and 903, as well as memory banks 902 and 904, havededicated read and write pipes for reading and writing data from and tostorage cells. This grouping allows for master device 130 to providealternate commands to alternate groups of memory banks that enable fullexternal interconnect or bus DQ utilization. Read data is output andinterleaved between the different groups of memory banks in anembodiment.

In an embodiment, a first data interconnect DQ-A having sixteen datasignal lines is coupled to memory banks 901 and 903 by read pipe 906 andwrite pipe 907. A second data interconnect DQ-B having sixteen datasignal lines is coupled to memory banks 902 and 904 by read pipe 908 andwrite pipe 909. A control interconnect RQ is also coupled to aninterface of integrated circuit memory device 900 to provide controlsignals to control logic 905.

Memory banks 901 and 903, as well as memory banks 902 and 904, are ableto operate independently. In other words, no timing constraint isimposed when one group of memory banks may be accessed relative to theother group of memory banks. This independent nature of memory bankgroups is derived from the fact that the memory groups are isolated fromeach other. The memory groups are sufficiently decoupled from each otherfrom an electrical noise standpoint that access to one memory group doesnot corrupt data in another memory group. More specifically, theactivation of one set of sense amplifiers associated with a memory groupdoes not corrupt the other set of sense amplifiers associated with theother memory group, regardless of the timing of the ACT commands. In anembodiment, electrical isolation between memory groups is achieved bypositioning an interface between memory groups.

FIG. 10 is timing diagram and bank content mapping 1000 illustrating afirst mode of operation using a quad column addressing mode of theintegrated circuit memory device 900 shown in FIG. 9. FIG. 10illustrates request packets provided on a control interconnect RQ bymaster device 130 to output a plurality of data values on interconnectsDQ-A and DQ-B from memory banks 901 and 903 as well as 902 and 904,respectively, in integrated circuit memory device 900. The timing of therequest packets and subsequent data output on interconnects DQ-A andDQ-B is similar to the timing constraints described above in regard toFIG. 3. An ACT command ACT B0 is provided on interconnect RQ to activatebanks B0 in memory banks 901 and 904. In an embodiment, a COL requestpacket B0 a B0 b and COL request packet B0 c B0 d is then asserted oninterconnect RQ by master device 130. In an embodiment, COL requestpacket B0 a B0 b and COL request packet B0 c B0 d are in a requestformat similar to a request packet 401 shown in FIG. 4. Fields C[8:4]contain a first column address for accessing data B0 a and fieldsCP[8:4] contain a second column address for accessing data B0 b in page1010 in banks B0 of memory banks 901 and 904, respectively. Likewise inthe second COL request packet B0 c B0 d, fields C[8:4] contains a firstcolumn address for accessing data B0 c and fields CP[8:4] contains asecond column address for accessing data B0 d in page 1010 in banks B0of memory banks 901 and 904, respectively. A PRE command PRE B0 is thenprovided on interconnect RQ by master device 130 and directed to banksB0 in memory banks 901 and 904. In an embodiment, data B0 a (128 bits or8 bits by 16 bits of data) is output on interconnect DQ-A during columncycle time interval t_(CC). Likewise, data B0 b is output oninterconnect DQ-B. During a next column cycle time intervals t_(CC),data B0 c and B0 d is output from integrated circuit memory device 900on interconnects DQ-A and DQ-B, respectively. The operation may then berepeated for memory banks B1, B2, B3, B4, B5, B6 and B7 in memory banks901 and 903 as well as 902 and 904. It should be noted that there is norestriction on accessing memory banks in a particular order in anembodiment illustrated by FIG. 10.

FIG. 11 is timing diagram and memory bank content mapping 1100illustrating a second mode of operation using a quad column addressingmode of the integrated circuit memory device 900 shown in FIG. 9. In anembodiment illustrated by FIG. 11, an integrated circuit memory device100 is operating at approximately 250 MHz (1/t_(CC)). It is typicallymore difficult to provide enough data to an interface 100 b with lowaccess granularity unless multi-column addressing is used as describedherein. In alternate embodiments, an integrated circuit memory device100 is operating at a relatively faster approximate 500 MHz. FIG. 11,like FIG. 10, illustrates request packets asserted on a controlinterconnect RQ by master device 130 to output a plurality of datavalues on interconnects DQ-A and DQ-B from memory banks 901-904 inintegrated circuit memory device 900. The timing of the request packetsand subsequent data output on interconnects DQ-A and DQ-B is similar tothe timing constraints described above in regard to FIG. 3. ACT commandsACT B0 and ACT B1 are asserted on interconnect RQ to activate memorybanks B0 and B1 in memory banks 901-904. In an embodiment, four COLrequest packets B0 a B0 b, B1 a B1 b, B0 c B0 d, and B1 c B1 d are thenasserted on interconnect RQ by master device 130. In an embodiment, COLrequest packets B0 a B0 b, B1 a B1 b, B0 c B0 d, and B1 c B1 d are in arequest format similar to request packet formats 801 and 802 shown inFIG. 4. Fields CP[8:4], C[8:4] and a SEL value contain column addressvalues for independently accessing four columns of page 1110 in memorybanks B0 of memory banks 901 and 904 and page 1120 of banks B1 of memorybanks 902 and 903. In particular, the first COL request packet B0 a B0 bcontains the column address for accessing data B0 a and B0 b in the page1110 in memory banks B0; the second COLM request packet B1 a B1 bcontains the column address for accessing data B1 a and B1 b in page1120; the third COLM request packet B0 c B0 d contains the columnaddress for accessing data B0 c and B0 d in page 1110; and the fourthCOLM request packet B1 c B1 d contains the column address for accessingdata B1 c and B1 d in page 1120. In an embodiment, PRE commands PRE B0and PRE B1 are then asserted on interconnect RQ by master device 130 anddirected to memory banks B0 and B1. In an embodiment, data B0 a (128bits or 8 bits by 16 bits of data) is output on interconnect DQ-A duringcolumn cycle time interval t_(CC). Likewise, data B0 b is output oninterconnect DQ-B. During a next column cycle time interval t_(CC), dataB1 a and B1 b is output from integrated circuit memory device 900 oninterconnects DQ-A and DQ-B, respectively. During a next column cycletime interval t_(CC), data B0 c and B0 d is output from integratedcircuit memory device 900 on interconnects DQ-A and DQ-B, respectively.Also, during a next column cycle time interval t_(CC), data B1 c and B1d is output from integrated circuit memory device 900 on interconnectsDQ-A and DQ-B, respectively. It should be noted that data output fromodd and even pairs of memory banks are paired to avoid conflicts.

The foregoing description of the preferred embodiments of the presentapplication has been provided for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit the preciseforms disclosed. Obviously, many modifications and variations will beapparent to practitioners skilled in the art. The embodiments werechosen and described in order to best explain the principles of theinvention and its practical applications, thereby enabling othersskilled in the art to understand the invention for various embodimentsand with the various modifications as are suited to the particular usecontemplated. It is intended that the scope of the invention be definedby the following claims and their equivalents.

1. An integrated circuit memory device, comprising: an interface; astorage array having a row of storage cells; and a column decoder toaccess the row of storage cells, wherein the integrated circuit memorydevice is operable in a first mode and second mode of operation,wherein: during the first mode of operation, the row of storage cells isaccessible from the interface in response to a first column address; andduring the second mode of operation, a first plurality of storage cellsin the row of storage cells is accessible from the interface in responseto a second column address and a second plurality of storage cells inthe row of storage cells is accessible from the interface in response toa third column address, wherein the first plurality of storage cells andthe second plurality of storage cells are concurrently accessible fromthe interface.
 2. The integrated circuit memory device of claim 1,wherein the first and second plurality of storage cells are accessibleduring a column cycle time interval.
 3. The integrated circuit memorydevice of claim 1, wherein a first plurality of data is output from thefirst plurality of storage cells onto the interface during a first timeinterval and a second plurality of data is output onto the interfacefrom the second plurality of storage cells during a second timeinterval.
 4. The integrated circuit memory device of claim 1, wherein afirst and second plurality of data is output from the first and secondplurality of storage cells, respectively, onto the interface during afirst time interval.
 5. An integrated circuit memory device, comprising:an interface; a first storage array having a first row of storage cells;a second storage array having a second row of storage cells; a firstcolumn decoder to access the first row of storage cells; and a secondcolumn decoder to access the second row of storage cells, wherein theintegrated circuit memory device is operable in a first mode end asecond mode, wherein: during the first mode of operation, the first rowof storage cells is accessible from the interface in response to a firstcolumn address; and during the second mode of operation, a first andsecond plurality of data stored in the first and second row of storagecells, respectively, is accessible from the interface in response to asecond and third column address, and a third and fourth plurality ofdata stored in the first and second row of storage cells, respectively,is accessible from the interface in response to a fourth and fifthcolumn address, wherein the first plurality of data and the secondplurality of data are concurrently provided at the interface, andwherein the third plurality of data and the fourth plurality of data areconcurrently provided at the interface.
 6. The integrated circuit memorydevice of claim 5, wherein the first and second plurality of data isprovided at the interface during a first time interval, and the thirdand fourth plurality of data is provided at the interface during asecond time interval.
 7. The integrated circuit memory device of claim6, wherein the interface is coupled to a first interconnect to transferthe first plurality of data and a second interconnect to transfer thesecond plurality of data.
 8. An integrated circuit memory device,comprising: an interface; a first memory bank having a first row ofstorage cells; a second memory bank having a second row of storagecells; a third memory bank having a third row of storage cells; a fourthmemory bank having a fourth row of storage cells; a first column decoderto access the first row of storage cells; a second column decoder toaccess the second row of storage cells; a third column decoder to accessthe third row of storage cells; and a fourth column decoder to accessthe fourth row of storage cells, wherein the integrated circuit memorydevice is operable in a first mode and second mode of operation,wherein: during the first mode of operation, the first row of storagecells is accessible from the interface in response to a first columnaddress; and during the second mode of operation, a first and secondplurality of data stored in the first and second row of storage cells,respectively, is accessible from the interface in response to a secondand third column address, and a third and fourth plurality of datastored in the third and fourth row of storage cells, respectively, isaccessible from the interface in response to a fourth and fifth columnaddress.
 9. The integrated circuit memory device of claim 8, wherein thefirst and second plurality of data is provided at the interface during afirst time interval, and the third and fourth plurality of data isprovided at the interface during a second time interval.
 10. Theintegrated circuit memory device of claim 8, wherein the interface iscoupled to a first interconnect to transfer the first and thirdplurality of data and a second interconnect to transfer the second andfourth plurality of data.
 11. A memory system comprising: a masterdevice to provide a first, second and third column address; and anintegrated circuit memory device, including: an interface coupled to themaster device; a first storage array having a first row of storagecells; and a column decoder to access the first row of storage cells,wherein the integrated circuit memory device is operable in a first modeand second mode of operation, wherein: during the first mode ofoperation, the first row of storage cells is accessible from theinterface in response to the first column address; and during the secondmode of operation. a first plurality of storage cells in the first rowof storage cells is accessible from the interface in response to thesecond column address and a second plurality of storage cells in thefirst row of storage cells is accessible from the interface in responseto the third column address.
 12. The memory system of claim 11, whereinthe second and third column addresses are transferred in a requestpacket by the master device.
 13. The memory system of claim 11, whereinthe first and second plurality of storage cells are accessible during acolumn cycle time interval.
 14. The memory system of claim 11, whereinthe master device is a graphics controller.
 15. The memory system ofclaim 11, wherein the master device is a memory controller.
 16. Thememory system of claim 11, wherein the master device provides a fourthand fifth column address, and the integrated circuit memory device isoperable in a third mode of operation, wherein: during the third mode ofoperation, a first and second plurality of storage cells in the firstrow of storage cells is accessible at the interface in response to thesecond and third column address and a second and third plurality ofstorage cells in a second row of storage cells is accessible from theinterface in response to a fourth and fifth column address.
 17. Thememory system of claim 16, wherein the second and third column addressesare transferred in a first request packet and the fourth and fifthcolumn addresses are transferred in a second request packet by themaster device.
 18. The system of claim 16, wherein the master device iscoupled to the integrated circuit memory device by a first and secondexternal interconnect, wherein a first plurality of data is output fromthe first row in a first memory bank onto the first interconnect duringa first time interval and a second plurality of data is output onto thesecond interconnect from the second row in a second memory bank duringthe first time interval.
 19. A method comprising: receiving a firstcolumn address to access a first plurality of storage cells in a row ofstorage cells during a first time interval; and receiving a secondcolumn address to access a second plurality of storage cells in the rowof storage cells during the first time interval.
 20. The method of claim19, wherein the first time interval is a column cycle time interval. 21.The meted of claim 19, further comprising: generating the first columnaddress by a master device; and generating the second column address bythe master device.
 22. The method of claim 21, wherein the first andsecond column addresses are in a request packet.
 23. A methodcomprising: receiving a first column address to access a first pluralityof storage cells in a first row of storage cells during a first timeinterval; receiving a second column address to access a second pluralityof storage cells in a second row of storage cells during the first timeinterval; receiving a third column address to access a third pluralityof storage cells in the first row during a second time interval; andreceiving a fourth column address to access a fourth plurality ofstorage cells in the second row of storage cells during the second timeinterval.
 24. The method of claim 23, wherein the first and second timeintervals are column cycle time intervals.
 25. The method of claim 23,wherein the first row of storage cells is in a first memory bank and thesecond row of storage cells is in a second memory bank.
 26. Anintegrated circuit memory device, comprising: a storage array having arow of storage cells; and means for accessing a first plurality ofstorage cells in the row in response to a first column address andaccessing a second plurality of storage cells in the row, during acolumn cycle time interval, in response to a first and second columnaddress.